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01 March 2009

You may be right handed, but we're all left hearted

Just as writing with my right hand eventually makes it hurt, while my left hand enjoys a relative stress-free life, my heart's left ventrical does much more work and is more stressed than my heart's right ventrical.

Because of the demand on the left heart, it also is larger, consumes more oxygen and is more vulnerable to oxygen imbalance. The lungs empty into the left heart so if it's not functioning to par, its possible it is unable to deliver blood to the circulation in the body. In addition to causing cerebral hypoxia, compromised systemic circulation decreases perfusion of kidneys activating the renin-angiotensin-aldosterone system. Angiotensin II increases peripheral resistance putting more strain on the left heart.

In most cases of heart failure, the left heart fails first. The right heart follows. But it is possible for the right heart to fail independently in primary lung diseases when pressure load on the right heart increases significantly.

Independent right-side heart failure can occur when there is resistance in the lung's vascular bed. The congestion of capillary beds include hepatomegaly and splenomegaly. Congestion of kidneys can decrease perfusion more than as would occur in left heart failure, resulting in increased fluid retention, edema, accumulation of impurities and waste. In time, the left heart will follow.

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About Me

I'm a science and health writer based in the Gilbert, Ariz., with a passion for good food combined with a good story. My background is in science communications with a master's of science degree in human nutrition and a bachelor's of arts degree in English. I've written for a variety of publications including Scientific American, Outside Online, the American Society for Nutrition's Nutrition Notes Daily, and the Institute of Food Technologists' Food Technology print magazine. I'm an active member of several respected organizations including the National Association of Science Writers and the American Association for the Advancement of Science. I'm also interested in wildlife conservation and am a member of the National Audubon Society and the American Society of Naturalists.